I've gone back and played with various simple panel designs and had success getting the scrollPane to activate every time. As such, I deducted that the issue is specific to this particular program.
I removed all other panels to take those out of the mix, simplifying the program above as much as possible. I then removed the setSize() on the frame and switched to pack(). When I ran the program, the window that opened was as small as possible, only big enough to show the
java icon, 2 resizing buttons, and the red x. When I stretched out the frame, the picture was there. That told me that Java was not seeing the size. I then decided it was time to pull up a console reading on that panel to confirm my suspicions. When I used System.out.println("Width: "+ centerComponent.getWidth()); and System.out.println("Height: "+ centerComponent.getHeight()); on the above program, I get the a dimension of the panel being height 0 by width 0.
So, I can now conclude that java jScrollPane will never work if it believes the panel is 0x0. That brings me to what ends up being the true issue. How do I get Java to see the drawn rectangles that are drawn from the constructor on another page?